(((hugs))) I feel your pain!
When I had my first, she was 7 lbs. I got a few stretch marks and my skin never went back to being as tight. I thought I understoond what loose skin was like. (insert my crazy laugh)
Then I had my next child. I had a 10 lb 11 oz baby. At 37 weeks, I measured about 42-43 weeks along. My belly was HUGE. I looked pregnant with twins. Everyone stared at me if I went in public. I have a small body and so it looked even more ridiculous.
That pregnancy left my belly muscles really messed up. I had a large spacing between them. Then my skin was so stressed that it was much saggier than my previous pregnancy. I had a lot more stretch marks, but they weren't nearly as bad as it seems like they should be, nor as bad as yours.
Then I've had two more babies since then and am pregnant with a another (so I'm on my 5th pregnancy). My other two babies were larger than average - 8 lbs 7 oz, and 9 lbs 7oz. This one is measuring large too. Having so many big babies has really done a toll of my muscles and skin. If they were more normal sized, I don't think it would be a big issue. But my skin has lost elasticity and it is very baggy...and dare I say it is kind of gross. I hate to describe anything with pregnancy as being gross, but I really feel like it is!
I get my body back to normal weight (little under 120 lbs) after I have my babies, but my belly always looks pregnant, and there is skin (not fat) that will hang over my pants, and it doesn't go away. It's very loose, saggy, wrinkly skin. I have a lot of it, and there is nothing I can do to get rid of it. Exercising and lotions do not help with this part. I've decided to wear maternity pants when not prego so that it'll fit my smaller body, as well as my tummy, and NOT give me a mushroom top.
For solutions - the stretch marks, give it time and find some really good lotions that will help diminish them. There is nothing that will make them go away, though. Almost all stretch marks will turn silvery after time. Though I know of another mom on here that said 4-5 years later, hers are still red!
For the skin, there's not really anything that can help that. If there's fat under there, you can try to lose the weight to trim it up more, but that's only going to make your skin seem even looser and more saggy.
The only REAL cure for the saggy skin is a tummy tuck.
I know a lot of women (myself included once upon a time) are totally opposed to having a tummy tuck. I didn't understand why women would have them. After having my first, my belly wasn't back to normal, but why would anyone want to hide the fact that they had a baby? There's nothing wrong with how your belly looks. And, that's true. BUT, what I didn't understand then was that there are a lot more severe cases than what I was going through. Many pregnant women have hardly any issues with their belly. Or it's mild. Usually it's not super severe. Your case was abnormal and you are now left with what sounds like an abnormal case of saggy skin.
Is it okay for obese people who lose a ton of weight to get a tummy tuck/skin reduction? I think so. And, I think this applies to pregnancy too. Why wouldn't it? If a mom feels insecure about her belly because she went through something natural, but some abnormal things happened (is it really normal to gain 5 lbs a day at the end?! I think not! Is it normal for someone my size to carry an almost 11 lb baby? No.), and I think it's okay to fix that.
Plus, there are other things you might want to look at that might actually be medical problems. Do you have a diastis recti? This is the spacing between your belly muscles. To check it out, lay on your back on the floor, with your knees bent/feet flat on the floor. Find your belly button. Then very slightly lift your head. Just enough so that your belly muscles tighten and you can feel where they are. Don't lift up past your shoulder blades. Just lift enough to feel the muscles. How many fingers can you fit in that space? If it's two or under, you can likely fix this with exercises ("Loose your mummy tummy" is a great book for this). If it's more than that, closer to 3 or more, from everything I have read, that is severe enough that no exercises will fix it. (and never do situps or crunches if you have a muscles spacing. it makes it worse!)
Anyway, so if you determine you have diasistic recti, that's not good. It can make you prone to umbilical hernias and severe lower back problems, as well as intestinal issues (from the hernia). I didn't realize all of this. I have a pretty severe diastis recti - about 3.5-4 finger spacing. With this pregnancy, I was having severe pain, and was diagnosed with a hernia. I also always deal with bad back pain. After I have the baby, I"ll need surgery to have the hernia fixed. Part of that surgery (as I'm told by my dr) is that they will need to stitch my muscles back together to keep a hernia from forming again. While frustrating, it's good because I don't want another hernia! And while I don't want surgery, I also don't want to look pregnant for the rest of my life. This surgery would help with that.
A general surgeon is who can do this, and insurance will cover it because it is a medical need. I'm considering a tummy tuck to remove all the extra flabby, wrinkly skin. I might need a plastic surgeon for that. I don't know yet. But hopefully he/she can come when they are fixing the hernia. I don't need a perfect looking belly. I'm actually quite attached to my belly because I carried my babies in there. But I also don't want to look pregnant forever or feel disfigured all the time because of all the extra skin. And I DO feel that way no matter how much I try to tell myself to not feel that way. It's like a super obese person loosing belly weight. You're left with a skin sag. Mine's severe enough that I truly would like it gone. Leave the stretch marks, no problem (though mine aren't as severe as yours), but I don't want ALL the extra skin.
I know I've rambled WAY TOO long about this. I just had a lot to say! It's been something I've been thinking about a lot once I was diagnosed with a hernia a couple weeks ago, and knew I was going to have to have surgery. I've realized the only reason I wouldn't do a tummy tuck was due to other people's opinion...other people, who none of them have a belly like mine, so they don't actually KNOW what it feels like. And most of those people are family members. Some of them are supportive though. I'm considering not sharing my news with them unless I feel like it. People can be judgmental, and i'm not interested in that:-) Especially when people aren't in my shoes (or your shoes!) and don't know what it's like.
Not suggesting you have to have a tummy tuck:-) Just suggesting that it really is the only way to remove skin as saggy and wrinkly as that. It won't heal over time. And for you to look to YOU and to YOUR feelings about it, and not let what other people might think about tummy tucks influence you (though, there are a ton of who are supportive of it!).
If you have a diastis recti, there might be a medical need (to prevent a hernia or fix one you might not know you have), and insurance will pay for it most likely. Then you can decide if you want to try to add a quick skin reduction surgery along with that...and feel normal again with the belly skin! And, of course, if you choose not to, no matter what happens to our bellies, it's always a mommy badge:-)